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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of electromagnetic engineering and science
Journal Basic Information
Journal DOI :
The Korean Institute of Electromagnetic Engineering and Science
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Volume & Issues
Volume 12, Issue 4 - Dec 2012
Volume 12, Issue 3 - Sep 2012
Volume 12, Issue 2 - Jun 2012
Volume 12, Issue 1 - Mar 2012
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Multihop Transmission Protocol Using Cooperative Diversity over Rayleigh Fading Channel
Duy, Tran Trung ; Kim, Jong-Soo ;
Journal of electromagnetic engineering and science, volume 12, issue 2, 2012, Pages 135~141
DOI : 10.5515/JKIEES.2012.12.2.135
In this paper, we propose a novel cooperative routing protocol (NCRP) for wireless networks. The proposed protocol uses cooperative transmission to improve end-to-end outage probability. The broadcast nature ensures that the destination can receive a packet from the source or from the relays and if it cannot correctly decode the packet, the successful relays will start a retransmission. The NCRP protocol can skip some transmissions from the intermediate relays, thereby reducing the total power consumption. Theoretical results are derived and verified by simulation results.
Cooperative Multi-Hop Transmission Protocol with Incremental Relaying Strategy over Rayleigh Fading Channel
Duy, Tran Trung ; An, Chong-Koo ;
Journal of electromagnetic engineering and science, volume 12, issue 2, 2012, Pages 142~147
DOI : 10.5515/JKIEES.2012.12.2.142
In this paper, we propose a novel protocol called Cooperative Multi-hop transmission using Incremental Relaying (CMIR). We evaluate the performance of the CMIR protocol by deriving expressions for the average end-to-end outage probability and the average number of transmissions. Monte Carlo simulations are presented to verify the accuracy of the theoretical analyses.
An Algorithm to Reduce the Number of Nodes in Active Spectrum Sensing Via Cooperative Sequential Detection
Truc, Tran Thanh ; Kong, Hyung-Yun ;
Journal of electromagnetic engineering and science, volume 12, issue 2, 2012, Pages 148~154
DOI : 10.5515/JKIEES.2012.12.2.148
In this paper, we propose an algorithm to conserve resources of the common control channel in a cognitive radio network by rejecting the redundant users using cooperative spectrum sensing. The proposed scheme is investigated under the paradigm of active spectrum sensing and a sequential detection technique. The algorithm is based on the J-divergence between the hypotheses of non primary user operation and the otherwise case. We select the most significant eigenvalues, which primarily affect the global statistical test. For the case where interference is from a secondary system transmission, a match filter is first employed to remove the degradation, and then the proposed algorithm is employed to remove the cooperative sensing nodes. Numerical results are provided and compared with conventional cases in order to validate the performance of the proposed algorithm.
A Wideband Circularly Polarized Pinwheel-Shaped Planar Monopole Antenna for Wireless Applications
Lee, Wang-Sang ; Oh, Kyoung-Sub ; Yu, Jong-Won ;
Journal of electromagnetic engineering and science, volume 12, issue 2, 2012, Pages 155~160
DOI : 10.5515/JKIEES.2012.12.2.155
A wideband circularly polarized pinwheel-shaped planar monopole antenna fed by a wideband feeding network is presented in this paper. The proposed antenna is formed by four wideband planar monopole antenna elements with aquadruple feeding network in order to improve the performance of circular polarization. Additionally, the antenna, which is introduced here, has a high gain in the z axis direction because of its folded antenna structure. The attractive characteristics of the proposed antenna are the wide impedance bandwidth of 87.3 % (1 GHz to 2.55 GHz), the 3 dB axial ratio (AR) bandwidth of 92.3 % (1.05 GHz to 2.85 GHz), and the maximum gain within the 3 dB AR bandwidth is about 8.24 dBic.
Comparison of the Measured Electrical Properties of Pig Internal Organs with the Given Values for Human Organs
Jung, Ji-Hyun ; Kim, Se-Yun ;
Journal of electromagnetic engineering and science, volume 12, issue 2, 2012, Pages 161~165
DOI : 10.5515/JKIEES.2012.12.2.161
The electrical properties of pig internal organs including lung, liver, heart, kidney, blood, stomach, and small intestine are measured using an open-ended coaxial probe and an improved virtual transmission-line model. The measured complex permittivities of the pig organs are compared with the given values of the corresponding human organs. A similarity between these values is confirmed. For organs such as lung, liver, heart, and kidney that have regular texture and contents, the complex permittivities are almost identical to those of the corresponding human organs. The complex permittivities of human and pig blood are also very close in value. However, relatively large deviations are observed for the cases of stomach and small intestine because the internal contents of these organs significantly affect the measured electrical properties.
Tunable Composite Right/Left-Handed Delay Line with Large Group Delay for an FMCW Radar Transmitter
Park, Yong-Min ; Ki, Dong-Wook ;
Journal of electromagnetic engineering and science, volume 12, issue 2, 2012, Pages 166~170
DOI : 10.5515/JKIEES.2012.12.2.166
This paper presents a tunable composite right/left-handed (CRLH) delay line for a delay line discriminator that linearizes modulated frequency sweep in a frequency modulated continuous wave (FMCW) radar transmitter. The tunable delay line consists of 8 cascaded unit cells with series varactor diodes and shunt inductors. The reverse bias voltage of the varactor diode controlled the group delay through its junction capacitance. The measured results demonstrate a group delay of 8.12 ns and an insertion loss of 4.5 dB at 250 MHz, while a control voltage can be used to adjust the group delay by approximately 15 ns. A group delay per unit cell of approximately 1 ns was obtained, which is very large when compared with previously published results. This group delay can be used effectively in FMCW radar transmitters.
A New Broadband Microstrip-to-SIW Transition Using Parallel HMSIW
Cho, Dae-Keun ; Lee, Hai-Young ;
Journal of electromagnetic engineering and science, volume 12, issue 2, 2012, Pages 171~175
DOI : 10.5515/JKIEES.2012.12.2.171
In this work, a new microstrip-to-substrate integrated waveguide (SIW) transition using the parallel half-mode substrate integrated waveguide (HMSIW) is proposed. The proposed transition consists of three sections : a microstrip, parallel HMSIWs, and an SIW. By inserting the parallel HMSIWs section between the microstrip section and the SIW section, the proposed transition can improve the return loss characteristics of the near cut-off frequency because the HMSIWs section has a lower cut-off frequency than the SIW section (8.6 GHz). The lower cut-off frequency is achieved through gradual electromagnetic field mode changes for a low reflection. The measured return loss is less than 20 dB in the of 9.1~16.28 GHz freqeuncy range for the back-to-back transition. The measured insertion loss is within 1.6 dB for the back-to-back transition. The proposed transition is expected to play an important role in wideband SIW circuits fed by a microstrip.
Effects of a Metal Plane on a Meandered Slot Antenna for UHF RFID Applications
Kim, Ji-Kwon ; Oh, Il-Young ; Koo, Tae-Wan ; Kim, Jun-Chul ; Kim, Dong-Su ; Yook, Jong-Gwan ;
Journal of electromagnetic engineering and science, volume 12, issue 2, 2012, Pages 176~184
DOI : 10.5515/JKIEES.2012.12.2.176
In this paper, the effects of a metal plane on the performance of a meandered slot RFID antenna are evaluated in a real environment, and 3 metal plane cases are considered (the most likely scenarios in which metal conductive materials are placed near the tag antenna). The metal plane effects can be categorized as matching degradation and antenna gain variation. First, matching degradation due to the antenna's induced mutual impedance is experimentally investigated. In addition, the gain variation is investigated to figure out the change in the radiation characteristics. With the derived antenna parameters, the read range is calculated with the Friis transmission equation and measured to analyze the effects of a metal plane on RFID system performance. The calculated and measured read range varies from 9.3 m to 19.1 m as the distance between the RFID antenna and the metal plane changes.
A Compact Triple Band Antenna for a Wireless USB Dongle
Lee, Seung-Hyun ; Sung, Young-Je ;
Journal of electromagnetic engineering and science, volume 12, issue 2, 2012, Pages 185~188
DOI : 10.5515/JKIEES.2012.12.2.185
A compact monopole antenna possessing triple resonance (
) characteristics for (USB) dongle applications is presented. The resonance characteristic
is determined by the overall length of the antenna. The monopole antenna acts as the main radiator for
as well as the coupling feeding structure for the parasitic resonators in
. The resonance characteristic
is achieved by a combination of the capacitance formed by the coupling between the top and bottom parasitic substrate resonators and the inductance generated by a via bridging the two parasitic resonators.